PAU Anglès 2000 · Setembre · Sèrie 2 · Part 1 · Reading comprehension

THE SEARCH FOR LIFE The table in Sarah Gavit’s sunny office at the Jet Propulsion Laboratory in California, is covered with discoloured pieces of metal, most of them shaped like bullets1. Sarah’s table is a museum of one of the most adventurous space experiments ever planned: two probes2 that will dig into the surface of Mars at 400 miles per hour and look out for signs of whether the planet did once support life. To design them, Gavit began building and testing prototypes in 1995. Late this week, if all goes well, two of these oval shells will cross the Martian sky. These probes, travelling at a terrific speed, will go deep into the ground. They will capture some soil3 and drop it into a little box for later analysis. In front of her computer at JPL, Gavit will be examining the data for hints of water ice, a sign that once, long ago, life might have existed on our sister planet. And if there is frozen water, there may still be liquid water deep in the warmer underground. It is spring in the Southern hemisphere of Mars, and the south polar ice is melting. Just as spring means the renewal of life on Earth, many scientists hope that the Martian spring will bring clues to the existence of life on the Red Planet. These days the signs of water on Mars have become even more puzzling. Earlier missions discovered deep channels running thousands of miles. They seem to have been formed by water –torrents running with the force of 10.000 Mississippi Rivers. But the channels do not continue far. They disappear really quickly. Where did the water go? Ten years ago some scientists thought that they could see long, curving lines in some old photos of Mars. New observations suggest that they may be ancient beaches. Why? On the one hand, the line stays at a near-constant elevation, which evokes the image of some kind of sea level. Also, these curves are as flat and smooth4 as the floors of the deepest seas on Earth, which are the result of sediments throughout centuries. For years the official view on Martians has been that the environment is too hostile for them: it’s cold and it’s dry, and the thin atmosphere is as useless against solar radiation as a paper umbrella against a big rainstorm. With no liquid water on the surface, the planet would not be able to sustain life. Or so it seemed. The fact is that on the Earth “we have found microbes living in complete darkness inside rocks in the dry valleys of Antarctica and eating hydrogen,” says Hubbard. Other microbes sustain life by dissolving minerals –they eat rocks. Others live in sulfuric acid, at 212 degrees Fahrenheit, or in extremely difficult environments as vinegar or ammonia. Apparently, life is pretty loose where it lives. “If life ever got started on Mars,” says Jim Head, “then I’d very difficult to eradicate it. Once the surface became inhospitable, life would go underground.” 1 bullet: bala / bala 2 probe: sonda / sonda 3 soil: terra / tierra 4 smooth: llis / liso PART ONE: READING COMPREHENSION Answer the following questions according to the information in the text “The Search for Life”. [1 point each correct answer] 1. What makes the presence of water on the Red Planet intriguing? 2. The text suggests two different views on the possibility of life in Mars. What are they? 3. What are the different steps in Sarah Gavit’s experiment? 4. Which of the following sentences summarises the text best? a) Life requires environmental conditions, among them water, which are not present on the Red Planet. However, water and life are extremely difficult to eradicate. In some scientists’ opinion, if water and life ever existed on Mars, there may be still some underground water and life today. b) Sarah Gavit built probes to confirm the existence, a long time ago, of deep water channels –torrents as powerful as 10.000 Mississippi rivers. Lines in old photographs suggest ancient beaches and deep-sea floors. Spring, with the south polar ice melting, is the best season for sending probes. c) Water i